Control mechanism



March 27, 1945. J, B OWN 2,372,311

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Gigi J. 5. BROWN CONTROL MECHANISM Filed April 17, 1939 12 Sheets-Sheet2 BY Jbm fl oz ATTORNEIQ March 27, 1945. J, 8, BRO N 2,372,311

CONTROL MECHANISM Filed April 17, 1939 12 Sheets-Sheet 3 41 Uta-bar B.Brzowu Arrqguzy.

March 27, 1945. J; 3 BROWN 2,372,311

CONTROL MECHANISM Filed April 17, 1939 12 Sheets-Shae; 4

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March 27, 1945. J. B. BROWN 2,372,311

CONTROL MECHANISM Filed April 17, 19:9 12 Sheets-Sheet 5 all INVENTOR.BY dEssE: E5. Baown March 27, 1945. .1. 8. BROWN CONTROL MEQQANISM FiledApril 17, 1939 12 Sheets-Sheet 5 m ZIIII/ INVENTOR. JESSE 5. Beoww BYATTORNEY.

March 27, 1945. BRQWN 2,372,311

CONTROL macmmsm Filed April 17. 19:59 12 Sheets-Sheet 7 INVENETOR. dasscB. 52.0%!)1 ATTORNEY.

March 27, 1945. J, B. BROWN 2,372,311

CONTROL MECHANI SM Filed April 17, 1939 l2 Sheets-Sheet 8 V INVENTOR. By1JE$3E- D. BQowN March 27, 1945.

J. B. BROWN 2,372,311

CONTROL MECHANISM Filed April 17, 1939 12 Sheets-Sheet 1O INVENTOR. dawn[5 62mm ATTORNEY.

k March 1945. J. 8. BROWN 2,372,311

CONTROL MECHANISM Filed April 17, 1939 12 Sheets-Sheet 11 lwENToR. BYdEssE B. BQOWH ATTORNEY.

March 27, 1945. J. B. BROWN 3 CONTROL macxmusu Filed April 17, 19:59 12Sheets-Sheet 12 l/llf'I/IIIIIIII/(IA 7 ViI/IIIIIIAWIIIYI) I V mrvmvmR. Ydrama fifirzovxm.

men?- Patented Mar. 27, 1945 CONTROL MECHANISM Jesse B. Brown, SouthBend, Ind., assignor to Bendix Aviation Corporation, South Bend, Ind., acorporation of Delaware Application April 1'7, 1939, Serial No. 268,356

4 Claims.

This invention relates to mechanism for operating power shovels, cranes,excavators and similar types of labor saving machinery and moreparticularly to the arrangement of several actuators therefor inrelation to one another. It relates to the remote controls for saidactuators and to the relation of said controls to each other.

An object of this invention is to provide various operating means andholding means arranged so that a single movement of therernote controltherefor releases one of the means and actuates the other.

A further object is the provision of a single control valve capable ofactuating a plurality of difierent operating cylinders eithersimultaneously if the instrumentalities associated therewith arenormally actuated simultaneously or alternatively ii theinstrumentalities are never operated at the same time.

Still another object of this invention is to provide a remote controlfor power applying means, together with means to limit the remotecontrol at times to a predetermined application but so arranged thatwith the shifting of a secondary element the power applying means may befully applied.

Another object of this invention is to provide control means in the formof a valve controlline two service outlet lines, so arranged that bothlines are subject to the operating medium pressure when the valve is inthe neutral position and operation of the valve in either directionreverses the pressure in one of the service lines.

A feature of this invention is the provision of a pair of clutch membersand a pair of brake members operated by a pair of remote controls; theclutches being paired with the brakes in such a manner that by remotecontrol either clutch may be actuated with the brake of the other pairand also so that both clutch members or both brake members may beoperated at the same time.

Other objects and features of the invention will be apparent from areading of the subjoined specification and claims and from aconsideraton of the accompanying drawings, in which:

Figure l is a side view of a power shovel illustrating the applicationof my invention:

Figure 2 is a diagrammatic view of the power shovel of F gure 1 showingthe actuating means for its various operations;

Figure 3 is a plan view of my novel hand control valve;

Figure 4 is a view partly in elevation and partly in section takensubstantially on line 4-4 of Figure 3;

Figure 5 is a sectional view taken substantially on line 55 of Figure 4:

Figure 6 is a sectional view taken substantially on line 6-6 of Figure4;

Figure 7 is a diagrammatic showing of the sw ng operation controlsystem;

Figure 8 is a view in vertical section of one of the hand operatedvalves shown in Figure 7:

Figure 9 is a view in vertical section of my novel valve whichautomatically controls the operation of the swing" brake, the valvebeing illustrated as in the normal or brake applied position;

Figure 10 is a fragmentary view in section showing the valve mechanismof Figure 9 in the brake released position;

Figure 11 is a diagrammatic showing in more detail of the swing" brakealso show in Figure 2;

Figure 12 is a side view in elevation showing the means provided tolimit the application of the hand valve to a predetermined degree inorder to obtain slip" in the clutch operated thereby;

Figure 13 is a perspective view of the stop of Figure 12, the stop beingshown also in dotted lnes in the position to permit unrestrictedoperation of the valve handle with which it is associated;

Figure 14 is a fragmentary view from beneath the chassis illustratingthe clutch and brake arrangement of the steering" control;

Figure 15 is a fragmentary view partly in elevation and partly insection illustrating the means of carrying the service lines from therotating platform to the non-rotating chassis through the pivotstructure;

Figure 16 is a sectional view taken substantially on the line I 6-46 ofFigure 15;

Figure 1'? is a diagrammatic showing of a modified form of controlsystem similar to that shown in Figure 7;

Figure 18 is a view in vertical section of one of the hand operatedvalves shown in Figure 1'1;

Figure 19 is a view in vert cal section of a valve of Figure 17 which islike the valve of Figure 9 arranged to control automatically theoperation of the swing brake, but modified for use in a vacuum suspendedsystem;

Figure 20 is a diagrammatic showing of a control system similar toFigure 17 incorporating therein another novel hand control valve;

Figure 21 is an elevational view of the novel hand operated valve shownin Figure and Figure 22 is a diagrammatic view of the detent mechanismfor holding the brakes applied should the power fail.

Referring now in detail to the drawings, it may be seen that I haveshown in Figure 1 a power shovel ll having a rotatable platform i2 uponwhich is mounted a gasoline engine i3 providing a source of power forthe operating mechanism. A boom I4 is mounted on a horizontal pivot IEon the forward end of the platform l2 and is provided with a dipper orshovel i6 mounted on a slidable member II. The member I! is slidablymounted in a journal l8 pivotaily mounted on the boom [4 and is alsoprovided with a rack ill by which the shovel is caused to move outwardlyor "crowd or to return or rack by a pinion gear associated with the racki ii and other gearing not shown. The shovel Ii is raised or lowered,pivoting on its mounting iii in boom H, by means of a "drag line orbucket line 2i suitably guided in a pair of sheaves 22 mounted on theouter end of the boom i4 and a sheave 22 secured to the shovel itself.It will be understood that the bucket line 2i passes around one sheave22, thence around the sheave 23, thence back around the other sheave 22and is then secured to the boom M at 24. The boom l4 pivoted at itslower end to platform i2 as at [5 has its outer end raised and loweredby means of a "hoist line 25 suitably guided in a pair of sheaves 26also mounted upon the outer end of the boom II and another pair ofsheaves 21 mounted in a swinging bracket 28 of a brace frame 29 and asingle sheave 8i mounted at the apex of the frame 29. Thus it will beseen that the holst" line 25 (spooied on its drum 32 to raise the boom Hor off to lower it) passes around the sheave 3i, thence around one ofthe sheaves 2B, thence to the pair of sheaves 21, thence to the othersheave 26 and returns to the bracket 28 to be secured thereto.

The platform I2 is mounted on a pivot 33, details of which will behereinafter described, and is provided with suitable gearing in orderthat the platform i2 may be caused to rotate or swing in eitherdirection upon the pivot 33 under control of an operator. Further, theplatform I2 is provided with guide rollers 24 confined in a guid 35mounted on a chassis 26, the chassis being provided with caterpillartreads or crawlers 81.

The operating mechanism and controlling mechanism are better shown inFigure 2. It will be noted that a vacuum system is provided including atank Ii, wherein a vacuum is maintained by a vacuum pump 42 associatedwith the engine l3. In communication with the tank or vacuum source IIby means of conduit generally designated by numeral 43 are controlassembli s 44, 45, 4G. 41, 48 and 49. each having valves associated withhand controls. Also associated and in communication with the vacuum tankll through conduit 48 are foot pedal controlled valves ii and 52. Alsoconnected by conduit 43 and branch conduits 53 and 54 is an automaticcontrol valve 55. Hand control valves 44, l5, l6, ll, 48. 49 and footpedal controlled valves SI and 52 control the operation of the boom ll.rack member l1, shovel l6, rotation of the platform i2 and operation ofthe caterpillar crawlers 31. Valve 55 is an automatic valve operated bydiflerentials of pressures to operate the brake restricting rotation ofplatform i2. The manner in which these control units operate the variousparts will now be described in detail.

The control valve assembly 45 controls a system comprising clutchoperators (power cylinders) and as this system is similar in manyrespects to those systems controlled by hand control valve assemblies46, ll, 48 and 49, it may be considered typical thereof. The system maybe readily appreciated from Figure 2 while the hand control valveassembly 45 is described in detail with reference to Figures 3, 4, 5 and6.

The control valve assembly 15 controls the movement in and out of therack member H for crowd and rack" operation of the bucket It. Thecontrol mechanism which controls the crowd and rack" operation may alsoin the well-known manner control the travel" operation which is forwardand rearward movement of the entire outfit and the operation of thetravel" may be in one or more speeds.

Hand control assembly 45 is connected by conduits 58 and 51 respectivelyto a power cylinder 50 arranged to actuate a "crowd" clutch 59 and to apower cylinder 6| arranged to actuate a "rac clutch 62.

Valve 45 is shown in detail in Figures 3, 4, 5 and 6 and comprises (seeFigure 6) an upper portion 63 and a lower portion 64 having securedtherebetween, suitably gasketed, a plate member 65 providing seats forvalve members housed in the lower portion 64. An operating lever 68 issecured to a shaft member 61 journaled in a partition 68 dividing theupper portion 53 of valve 45 into two chambers (see Figure 4) i9 andIll. The shaft member 6'! rocked by the lever 66 is flattened at eachend to provide line contact with cam surfaces 12 of valve operatingrockers i3 and 14 respectively pivoted on pins 15 and 16 secured inpartition 68. In Figure 5, it may be noted that the lower portion 64 ofthe valve 45 is provided with four vertically disposed bores formingvalve chambers ll, 18, I9 and 80. Bores l1 and I9 are in opencommunication by means of a diagonal passage 82 as are the bores I8 andBil by means of a passage 83. Thus atmospheric pressure is maintained inchambers 18 and all by air entering through conduit 84 provided with anair cleaner 85 (Figure 2) and subatmospheric pressure is maintained inchambers 11 and 19 through open communication with vacuum tank Ii bymeans of conduit B6. Lower portion 64 is also provided with verticallydisposed bores 81 and 88 providing through passages 89 and 90 opencommunication between the chambers Bil and 10 and conduits 56 and 51respectively. Thus the pressures prevailing in the chamber 69 arereproduced at the "crowd clutch power cylinder 58 through the passage89. bore 81 and the conduit 55 and the pressures prevailing in thechamber iii are reproduced at the "rack clutch power cylinder 6| throughthe passage 90, bore 88 and the conduit 51.

Bores l8 and 80 are each provided with a valve member 94 which controlthe air entrance into the upper chambers 69 and 'lil. Bores l1 and 19are each provided with a valve member 95 which control the vacuumentrance to said chambers 69 and 10. Valve members 94 are slightlyremoved from their seats on member 55 when the valve handle 66 is in theneutral position as shown in Figure 6, thus subjecting the chambers Bi!and Ill and the various members controlled by the valve assembly toatmospheric pressure.

From the above, it is readily seen that the control valve assemblycontrols two operators; name- 1y, that of moving the shovel I6 outwardlyand that of returning it. The valve mechanism is such that the actuationof neither of the operations is possible when the control Valve assemblyhandle is upright in the neutral position. Movement of the handle in onedirection energizes the mechanism to perform one operation anddefinitely maintains the other mechanism inactive and movement of thehandle in the other direction beyond neutral reverses the procedure,maintains the previously energized mechanism inactive, and energizes thepreviously inactive mechanism.

The control assembly 44 controls the rotation of the platform I2 and thesystem operated thereby is separated and shown in Figure 7 for clarity.

Referring to Figure 7. a valve I III is operated by forward movement ofthe handle I02 as indicated by the arrow F through linkage I03 whichactuates the valve IOI through tension only. It will be noted that thislinkage or chain I03 collapses in compression and transmits incompression no movement whatsoever to the valve parts associatedtherewith. The valve IOI when actuated by forward operation of a handleI02 connects suction from a conduit 43 through a conduit I04 to a powercylinder I05 to operate a clutch I03 to rotate the platform I2 andswing" its associated boom I4 (not shown in Figure 13) in one direction.Branch conduit I01 connected through conduit I04 with the valve IOIleads to a valve 55 and is arranged to energize the valve to operate apower cylinder I08 to release a swing brake I09 normally held applied byspring I I I. Likewise, rearward movement of the handle I02 operates avalve II2 through suitable linkage I I3 also operable in tension only. Aconduit II4 connects valve II2 with a power cylinder II5 which operatesa clutch H6 to rotate the platform I2 and swing" its associated boom I4in the reverse direction. A branch conduit I I1 of the conduit II4connects the valve II2 with the va ve 55 to actuate the valve mechanismtherein to also release the brake I03 as before.

It is sometimes desirable to operate the swing brake apart from the"swing" operation described above. This is accomplished through athree-way valve IIB interposed in the conduit I01. This valve H8 is alsoconnected to the source of suction 4| through a branch conduit II9 ofthe conduit 53. Valve 55 is connected by a conduit I2I with controlassembly 41 so arranged that upon movement of the handle of the assembly41 forward as indicated by the arrow G. it connects the vacuum tank 4Ithrough the conduit 43. the valve assembly 41 and the conduit I 21 withone chamber of the valve 55. Assuming that valve H8 is set to leave theconduit I01 open, this has no effect upon the operation of valve 55 butif the valve H8 is turned to connect suction line Hi! to the upperchamber of valve 55, operation of the assembly 41 is effective to allowthe application of the brake I09 as will be later more fully described.

Figure 8 illustrates in greater detail the valve IOI. As the valve I I2is a duplicate of the valve IN, a description of the valve IOI willsuffice for both. The valve I'll is provided with a spool type valvemember I22 which brings into open communication the conduit I04 andatmospheric entrance ports I23 when in its lowermost position as shown(with the operating handle in the uplie right or neutral position).Movement of the hand lever I 02 forward raises the valve member I22 toclose off the air inlet ports I23 and open communication between theconduits I04 and H9. The establishment of open communication between theconduits I04 and H9 subjects the power cylinder I05 and the upperchamber of the valve 55 to the subatmospheric pressure of tank 4I. Acompression spring I24 and suction on the underside of diaphragm I25when in the raised position tend to return the valve member I22 to thenormal position first described. The underface of the diaphragm I25 issubjected at all times to the pressure in the cylinder I05 inasmuch asthe conduit I04 is connected by a passage in the form of a slot I25 withthe space below the diaphragm I25, The space above the diaphragm I25 isconnected to the atmosphere and therefore the diaphragm is urgeddownward at all times by a force comprising the effort of spring I24 andthe differential in pressures acting on its faces equivalent to thedifferentials in pressures in the cylinder I05. The valve member I22 11moved from the position shown upward, by tension on the linkage I03 whenthe handle I02 is moved forward. Thus the force exerted by the cylinderI05 is accurately controlled. The cylinder I05, it will be noted has twochambers. one on each side of the piston in the cylinder. The chamber tothe right of the piston is at all times open to atmosphere. The chamberto the left of the piston, since it is connected to conduit I04, has thesame pressure as conduit I04, and this pressure is determined by theposition of valve member I22, 1. e., by the movements of valve memberI22 opening or closing the ports H9 and I23. Since passage I26 connectsconduit I04 to the chamber in valve IOI which is just below diaphragmI25, the pressure conditions under diaphragm I25 are the same as thoseon the left side of the piston in cylinder I05. The chamber abovediaphragm I25 is open to atmosphere, and, therefore, the same pressuredifferential prevails over diaphragm I25 as prevails over the piston incylinder I 05. Since the pressure differential over diaphragm I25 tendsto move valve member I22 downward and thereby close port I I9 and openport I23 to release the clutch, the operator will feel this pressurereacting against his manipulation of valve I 0|, the reaction beingproportional to the force exerted by cylinder I05.

The automatic control valve 55 (Figure 9) is provided w th an upperportion comprising three chambers I21. I28 and I29 open'ng into whichare conduits I01, H1 and I2I respectively. Separating the chambers I21and I28 is a diaphragm I 3| and separating chambers I28 and I29 is adiaphragm I32 of sub tantially twice the effective area of d aphragmI3I. A valve operating rod I33 having the diaphragrns I3! and I32secured to its up er end is slidably mounted in a part ton I34 formingthe lower wall of chamber I29. Suitable pack n I35 is provided toprevent leakage at this point. A rhamber I36 in the lower portion ofvalve has communication to the atmospbere throu h an air cleaner I31 andvacuum conduit 54 controlled by valves I38 and I33 respectively actuatedby a rocker link I4I secured to the lower end of valve rod I33. Thechamber I36 is also in open communication with power cylinder I00through con ut I42. Thus it wi l be seen that with the val e rod I32down as shown in Figure 9. the valve I38 leading to atmosphere is openand the valve I39 leading to suction is closed, thus providing nodiflerential pressure to the power cylinder I a and allowing theapplication of the "swing brake through tension spring III. As shown inFigure 10 with the valve rod I32 up, the valve I33 leading to atmosphereis closed and the valve I33 controlling the suction is open, placing thechamber I36, conduit I42 and power cylinder I08 under subatmosphericpressure to pull the brake I03 to a released position against thetension of spring III. It is to be understood that when the valve memberI38 and I33 are moved from the position shown in Figure 9 to theposition shown in Figure 10, there is an intermediate lapped positioninasmuch as the valve I38 is seated firmly before the valve I33 israised from its seat. It is also to be noted that a diaphragm I43secured near the lower end of the rod I33 is perforated so that theportion of the chamber I36 above the diaphragm I43 is in communicationwith the lower portion at all times. In this connection, it will be seenthat th diaphragm I43 serves only to maintain the lower portion of valverod I33 centrally located.

The swing" brake may be arranged as shown in Figure 11 and is generallydesignated by the numeral I 03. The brake I03 comprises a band I44 whichembraces a member I45 forming a part of the platform I2 which it isdesired to hold against rotation. The band member I44 has its ends I46and I41 slidably mounted to anchor in the ends of a slot I48 of a fixedmember I43. On the end I46 of the band I44, there is mounted a bellcranklever II which has on one of its arms I 52 a link I53 fulcrumed as atI54. The link I53 is rotatably secured at its other end to the anchorend I41 of the brake band I44. An arm I55 of the bellcrank lever I5I isconstantly urged in a clockwise d rection as seen in Figure 11 by aspring III suitably secured to the free end thereof. It will be notedthat the arm I52 of the bellcrank lever I5I forms a toggle with linkI53, and thus movement of the arm I52 in a counter-clockwise directionunder the influence of the power cylinder I08 tends to release the brakeI09 and clockwise movement of the arm I52 influenced by the spring I IIthrough arm I55 tends to apply the brake I09. It will be understood thatthe spring III keeps the brake I09 applied at all times except when heldreleased by the energizing of the power cylinder I08.

The valve assembly 41 is exactly the same as valve assembly 45 disclosedin detail in Figures 3, 4, 5 and 6. The bore 81 is connected to conduitI2I however. The bore 83 operates the hoist clutch and will be laterdescribed.

The operation of the system shown in Figure 'l is as follows: Forwardmovement, as indicated by the arrow F, of the handle I02 through linksI03 closes the atmospheric entrance I23 or the valve IM and openscommunication between the vacuum tank 4I and the clutch power cylinderI05 through conduits I04 and II 3 to apply the left hand swing clutch.Communication is also established through branch conduit I01 andthree-way valve H8 with the upper chamber I21 of valve 55. Inasmuch asat this time chamber I20 is connected through conduit Ill and valve I I2 with atmosphere and chamber I23 is also connected with the atmospherethrough conduit HI and valve 41, this connection of chamber I21 withsuction through conduit I01 and the valve IOI causes upward movement ofthe diaphragms I 3| and I32 and the rod I33. This actuates valve 55 toopen communication between vacuum tank H and power cylinder I08 torelease the brake I 03 otherwise held applied by tension of the springIII. Movement of the handle I02 to the rear of the neutral positionactuates the valve II2 to open vacuum communication to the powercylinder II5 through conduit II4 to apply the right hand "swing" clutchand also through the conduit I I1 to the intermediate chamber I28 of thevalve 55. This connects the chamber I23 with suction and inasmuch as thechambers I21 and I23 are connected through their respective val es INand 41 with atmosphere and inasmuch as the area of the diaphragm I32 isdouble the area of the diaphragm I 3| the diaphragm and the valve rodI33 are raised. This actuates the valve members I38 and I33 and releasesthe brake I09 in the manner described above.

It is sometimes found desirable to operate the swing" brake I09 whollyindependent of the control through handle I02. When this is desired themanually operated three-way valve I I3 is set in it other position toclose oil communication to conduit I01 and open communication betweenthe vacuum tank 4| and the upper chamber I21 of valve 55 to actuate thevalve rod I33 upwardly and in turn actuate the valve mechanism toenergize the power cylinder I08 to maintain brake I 03 in the releasedposition. Now, with forward movement of the control handle oi valve 41,previously described, vacuum or subatmospheric pressure is admitted tothe lower chamber I23 of valve 55 through conduit I2I to actuate thevalve rod I33 downwardwly and admit air to the power cylinder I08, thuspermitting spring III to apply the swing brake. Return of the handle ofvalve 41 to the neutral position admits atmospheric pressure to thelower chamber I23 of valve 55, thus making the vacuum in the upperchamber I21 effective again to actuate the valve rod I33 upwardly andadmit subatmospheric pressure to power cylinder I08 to release the brakeI03.

Referring now again to Figure 2, hand control valve assembly 46 isexactly like the control valve assembly 45 described above. The lowerend of bore 61 (Figure 4) of the valve assembly 46 is however connectedto a conduit I56 (Figure 2) leading to a power cylinder I51 associatedto actuate a dipper trip latch on the dipper or shovel I6. The lower endof bore of the valve assembly 46 is however connected to a conduit I58leading to a power cylinder I53 arranged to actuate a clutch I6Iassociated with a drag line drum I62.

Moreover, there is provided an adjustable stop for the valve assemblyhandle. As may be seen in Figures 12 and 13, the valve assembly handleI63 has cooperating therewith a pivotally mounted member I64 providedwith an adjustment screw I65. The screw I65 is arranged to limit themovement of the handle I63 when the member I64 is in the position shownin full lines. When the handle I63 is so limited the rate of evacuationof the power cylinder I53 is metered in order to slip" the clutchassociated therewith. The member I64 may be moved out of the path ofmovement or the handle I63 to the position shown in dotted lines inFigure 13 so as not to limit the movement of handle I63 and the valve 46may then be operated in the usual manner.

The hand control valve assembly 41 is provided as described above sothat the brake I03 may be controlled separately from the clutches I08and H6 when desired. The hand control valve assembly 41 is connected bya conduit 86 to the vacuum tank M by means of the conduit 43 and to theair cleaner 85. Also associated with the hand control valve assembly 41as by a conduit I81 connected to the bore 88 is a power cylinder or airmotor I58 arranged to actuate a clutch I89 on a hoist drum 32 in axialalignment with the drag line drum I52. Thus it will be seen that the twofunctions of control valve assembly 41 are to separately operate theswing" brake and control the clutch to raise the boom I4. Lowering oithe boom I4 is accomplished in the usual manner by releasing the clutchand allowing the weight of the boom to pull the hoist line off of itsdrum until it is checked by its associated brake or reengagement of theclutch.

Hand control valve 48 and 49 control the steering" of the power shovelII and as the function and systems are similar they may be consideredtogether. The steering is accomplished through movement of thecaterpillars or crawlers 31. The control valve assembly 48 actuates themechanism for movement and restriction of movement of the crawler on oneside of the power shovel and likewise the control valve assembly 48actuates the mechanism of the crawler on the other side. It will also benoted that the conduits from the control valve assemblies 48 and 48mounted for the operator on the rotatable platform I2 must pass throughthe pivot 33 to the non-rotating chassis 35 which supports the steeringmechanism actuators controlled thereby. The hand control valve assembly48 similar in structure and operation to the valve 45 is connected byconduits HI and I12 passing .through the pivot 23 of platform I2 toopposite ends of a double acting power cylinder I13 and similarly valve48 is connected to a power cylinder I14 by conduits I15 and I16.

The steering arrangement is better shown in Figure 14 and comprises asbefore mentioned, two similar system each applied to a side of thecrawler mechanism. Double acting power cylinder I13 and cylinder I14 areeach actuated by suction to move an associated bellcrank lever I11through piston rods I18 and links I18 secured at one end to a fixed partof the crawler chassis. The levers are provided with thrust members I8Iadjacent their pivotal points I82 to actuate clutches I33. Arms I84 oflevers I11 beyond the pivots I82 are provided with adjustable linkssecured at their outer ends to brake bands I85. In this arrangement itcan be seen that suction applied through conduit I15 and air throughconduit I18 will move the piston in the cylinder I14 to the rightagainst the tension of spring I38 to apply the right-hand clutch I83 andrelease the right-hand brake I85. Conversely with suction appliedthrough conduit I16 and air supplied through conduit I15 the piston willbe urged to the left to disengage the righthand clutch and apply theright-hand brakes. The left-hand clutch and brake are similarlycontrolled by valve 48. Thus through the hand valves 48 and 49 eithercrawler may be actuated or either one held against movement to serve asa pivot in steering or both may be urged into motion at the same time orheld against movement as during a strictly dipper operation.

It is to be understood that the mechanism used to induce movement to thecrawlers 31 may be in the well-known manner reversed to 1m,- partrearward as well as forward movement thereto. The springs I88 constantlyurge the brakes I into holding position to prevent loss of control inevent the suction fails.

With reference to Figures 15 and 16, it will be seen that communicationbetween the fixed chassis 36 and the rotatable platform I2 is providedthrough a tubular member I88 secured to chassis 35. Within the memberI89 there are secured against displacement several tubes I8I, one beingprovided for each line for which communication is to be established. Thelower ends of tubes I8I are secured to outlets I82 and the upper endsterminate at outlets I83 positioned at different levels with respect toeach other and to align with annular channels I84 provided by collars Iassociated with conduits I1I, I12, I15 and I16. Collars I85 embracingtubular member I89 are permitted to rotate thereon and held againstaxial displacement by cap or nut I86. Suitable packing rings I81 preventsuction loss at the localities of relative movement.

Means are provided to operate the crowd" and "rack" brake and the dragline brake. Inasmuch as these are not operated together, I provide asingle brake pedal and brake valve associated therewith to control bothof these operaticns. Thus I obtain simplicity and stil1 provide a brakewhere needed for each of the operations. This is done through theaddition of a threeway valve interposed in the conduit between the footpedal actuated valve and the two separate braking systems. Selection ofthe system to be braked is accomplished through the manual setting ofthe three-way valve by the operation prior to beginning operations. Inthis manner the crowd" and "rack operation is braked in one position ofthe three-way valve and the "drag line drum is braked in the otherposition thereof. It is to be understood that the two operations brakedin this manner under a single foot pedal do not at any time requirebraking simultaneously.

A foot pedal I88 (Figure 2) is connected by suitable linkage to actuatea valve 5| similar in structure and operation to the valve I8lillustrated in Figure 8. Adjacent the valve 5| and interposed in theoutlet conduit I99 to control communication of the valve 5| to conduits28I and 282 is a three-way valve 283. With the threeway valve 283 in oneposition, the valve BI is in communication through the conduit 28I witha power cylinder 284 arranged to actuate a "crowd" brake (not shown).With the three-way valve 283 turned to its other position, the valve 5|is connected through conduit 282 with a power cylinder 285 arranged toactuate a brake 2I1 controlling the drag line" drum I62.

Inasmuch as the hoisting and lowering of the boom I4 is necessary inalmost all of the operations of the power shove], it is provided with aseparate brake system under the control of a foot pedal 288. Foot pedal288 is arranged through suitable linkage to actuate a valve 52 alsosimilar in structure and operation to the valve I8 I. The valve 52 isconnected by a conduit 281 with a power cylinder 288 arranged to actuatea brake 2I6 controlling the "hoist drum 32.

It will be readily seen that should vacuum fail for any reason during abraking operation of the hoist or drag line mechanism serious damage orinjury might result. As a safeguard I equip the brake applying mechanismassociated with these two brakes for this emergency. Bars 288 and 2, aswill be more clearly seen in Figure 22, are each formed with ratchets atone end and are secured at their other ends to the brake applying levers288' and 2H. The ratchet teeth are formed for engagement with detents H2and 2I3. The detents are normally held out of engagement by suctionacting on diaphragm power cylinders 2H and 2I5. Should a line fail orsuction loss occur for any reason, the loss of suction permits a springacting on the power cylinder diaphragms to move the diaphragm in adirection opposite to that in which they are urged by the suction. Thusit will be seen that the detent will be immediately brought intoengagement with the ratchet teeth provided on the rods 209 and 2| I. Inthis manner the brake will be held applied to the degree in efiect atthe time the suction loss occurred. The power cylinder 2 I 4 actuatesthe safeguard mechanism of the hoist drum brake H6 and similarly powercylinder 2I5 actuates the safeguard mechanism of the drag line brake 2".

In Figure 17, I have shown diagrammatically a modified system foroperating the swing clutches and brake using vacuum suspended cylindersinstead of air suspended cylinders. The system shown is substantiallythe same as that shown in Figure 7 and like elements have beendesignated by the same numerals with the addition of 200. However, thecylinders 305 and 3l5 have one end thereof connected through the conduit243 with the vacuum tank so as to maintain a continuous substantiallyuniform subatmospheric pressure in these portions of the cylinders. Theopposite ends of the cylinders 305 and 3I5 are connected respectivelythrough conduits 3M and 304 to valves 312 and 30L The connections fromthe valve 241 to vacuum and to the atmosphere are reversed and the powercylinder 308 has one end connected to the valve 255 through conduit 342and has its opposite end connected to the vacuum conduit 253. The valve3i2 is shown in detail in Figure 18 and includes movable poppet valvemembers 320 and 322 arranged to connect the conduit 3 either with theatmosphere through an air cleaner M or with vacuum through conduit 243.The valve is normally held in a position in which the vacuum conduit 243is connected to the control conduit 3 by reason of the fact that thevalve element 320 is held oif of its seat by difierentials in pressureacting on opposite sides of the diaphragm 330 and the valve element 322is at the same time maintained on its seat. However, movement of thehandle 302 is effective to move the rod 239 downward reversing thepoppet valve and opening communication between the atmosphere throughthe air cleaner M0 and the control conduit 3 l4 leading to the powercylinder.

The valve 255 is shown more clearly in Figure 19. It correspondssubstantially to the valve shown in Figure 9 and like parts aredesignated by the same numerals with the addition of 200. However, thevalve rod 333 is normally raised and has connected to the upper endthereof an extension 240 provided with an associated spring 250 tendingto keep the valve raised. The tension on the spring may be varied byadjustment of the nuts 260.

In Figure 20, I have shown another arrangement for operating the swingclutches and brakes similar to the arrangement shown in Figure 17 andlike parts therein have been designated by the same numerals with theaddition of 200. However, the valve |2 is used instead of two valves andis so arranged that when in the neutral position both of the clutchcylinders 505 and 5|5 are connected through the valve 5l2 to vacuum.When the handle 502 is moved in one direction, it connects atmosphere tothe clutch cylinder 505 and when it is moved in the opposite direction,it connects atmosphere to the other cylinder 5 I5. In connecting therespective clutch cylinders to atmosphere, it will be seen that movementof the valve rod 433 when opening the atmospheric poppet valve 520closes the vacuum poppet valve 522, raises the vacuum poppet valve 522'further from its seat and presses the atmospheric poppet valve 520' morefirmly on its seat. The diaphragm 530 provides a reaction inasmuch asthe cylinder 5I5 is connected through the conduit 5|! and the bore 5' tothe reaction chamber 50I, and the cylinder 505 is connected through theconduit 504 and bore 58! with the reaction chamber 535. The manner inwhich reaction is secured is as follows: In released position thepistons of cylinders 505 and 5l5 are submerged in vacuum. When either ofthe cylinders is to be actuated, atmosphere will be admitted bl means ofvalve 5i2 to the left side of the piston in the particular cylinderdesired to be operated. If cylinder 505 is to be actuated valve stem 435is moved to open conduit 504 to atmosphere. Conduit 5, leading tocylinder 5i 5, remains in vacuum. Since conduit 5 is connected by bore5H with chamber 5, that chamber will contain vacuum. Chamber 595. beingconnected to conduit 504, will have atmosphere admitted thereto at thesame rate as atmosphere is admitted to cylinder 505. The result will beto create a pressure differential over diaphragm 530 tending to move thevalve member 430 downward. As this happens, valve element 522a opens toadmit vacuum to conduit 504, tending to return the piston cylinder 505to released position. This releasing pressure constitutes the reactionagainst operators manipulation of valve 5 l 2.

The same principles apply when cylinder M5 is actuated. In this caseconduit 5 and chamber 58! are open to atmosphere, conduit 504 andchamber 596 being open to vacuum. The pressure differential overdiaphragm 530 now tends to move valve member 430 upward to move valveelement 522 and open conduit 5 to clutch releasing vacuum.

It is to be understood that the above described embodiment of myinvention are for the purpose of illustration only and various changesmay be made therein without departing from the spirit and scope of theinvention.

I claim:

1. In power shovel apparatus a dipper, means for raising said dipper, ahoist clutch for actuating said means. a power cylinder for actuatingsaid clutch, a platform, means for swingin said platform, a swing brakefor preventing said platform from rotating, a power cylinder foroperating said brake, and a valve assembly having a handle arranged inone position to operate said hoist clutch and arranged in anotherposition to alternatively operate said swing brake.

2. A power apparatus for controlling the operation of a rotatableplatform member said apparatus including a clutch for actuating saidmemher for rotation in one direction, a clutch for actuating said memberfor rotation in the opposite direction, a brake for holding said memberstationary, a power cylinder for engaging one of said clutches, a powercylinder for engaging the other said clutch, a spring for applying saidbrake, a power cylinder for releasing said brake, and valve mechanismfor controlling the operation of said power cylinders including a relayunit consisting of a three-way valve and power means for operating saidrelay valve, a manually operated master control valve for controllingthe operation of the power means of said relay valve and other manuallyoperated valve means for controlling the operation of the brakeoperating cylinder independently of the operation of said master controlvalve.

3. A power apparatus for controlling the operation of a rotatableplatform member said apparatus including a clutch for actuating saidmember for rotation in one direction, a clutch for actuating said memberfor rotation in the opposite direction, a brake for holding said memberstationary, a power cylinder for engaging one of said clutches, a powercylinder for engaging the other said clutch, a spring for applying saidbrake, a power cylinder for releasing said brake, and valve mechanismfor controlling the operation of said power cylinders including a relayunit consisting of a three-way valve and spring and pressurediilerential operated power means for operating said three-way valve, amanually operated master control valve for controlling the operation ofthe power means of said relay valve and other manually operated valvemeans for controlling the operation of the brake operating cylinderindependently 01' the operation of said cylinder by the master controlvalve said other manually operated valve means including two separatecontrol valves operable to effect a pressure diilerential operation ofthe aforementioned power means to effect a release of the brake and alsooperable to eiiect a spring operation of said power means to makepossible an application of the brake.

4. A power apparatus for controlling the operation of two clutches and abrake of the power plant of a power shovel said apparatus including a.single acting pressure differential operated motor for operating one ofsaid clutches, a single acting pressure differential operated motor foroperating the other of said clutches, a single acting pressurediflerential operated motor for operating said brake and valve means forcontrolling the operation of said motors including a relay valve, amanually operable selector valve for controlling the operation of saidrelay valve to efiect an operation of all three of the aforementionedmotors, and two separate manually operated valves for independentlycontrolling the operation of said brake operating motor.

JESSE B. BROWN.

